The invention relates, generally, to conduits, e.g. splashblocks and hoses and, more particularly, to an automatically retracting splashblock or hose suitable for use as an extension on a down spout, a sprinkler hose, a pump hose and the like.
One such retractable hose consists of a vinyl tube having two steel wires imbedded therein where the steel wires are formed so as to have a coiled shape. The steel wires wind the vinyl tube so that it will normally be in a coiled or rolled configuration. When water is forced through the tube under pressure, the tube is unwound and the water is conveyed through the tube to a remote location. When the water pressure is removed, the metal springs automatically return the tube to the rolled position. The vinyl tube also can be provided with holes along its length to allow it to function as a sprinkler. Hoses with such coiled steel wire are disclosed in U.S. Pat. No. 3,035,779 which issued 1962 May 22 to O. P. Convis and U.S. Pat. No. 3,966,121 which issued 1976 Jun. 29 to B. A. Littman.
U.S. Pat. No. 2,814,529 which issued 1957 Nov. 26 to V. R. Arnt also discloses a retractable hose that uses a flat spring steel band, a strip of resilient material such as plastic or rubber or a helical spring to provide the retracting force. The rubber or plastic tube of Arnt is provided with holes and is intended to be used as a sprinkler.
U.S. Pat. No. 4,582,257 which issued 1986 Apr. 15 to F. Siegler discloses a perforated dual-tube retractable hose which uses flat longitudinal strips of vinyl plastic, e.g. styrene, as a spring mechanism. Styrene strips are inserted into two adjacently-joined tubes. The hose is then wound tightly on a core and strapped to prevent unwinding. The hose is then boiled in water to set the styrene into a "clock spring" configuration.
A major problem associated with all of the above-mentioned types of retractable hoses is that over time the springs will lose their "memory" such that the hose is not rewound to its proper position. The problem is compounded in prior art devices which use two springs because the force applied by each spring will differ as the springs lose their "memory", unless the springs are matched. Matched springs are quite expensive, however. In addition, the positioning and alignment of the springs relative to each other is crucial to the proper functioning of the springs in the hose.
Another problem with the prior art devices that use metal springs is that there is a high capital cost for the manufacture of the hose. Also, with hoses longer than approximately 1.2 meters it becomes increasingly difficult to ensure that the two springs are kept in alignment, because of the characteristics of the metal wire spring. Because these hoses use two springs, each of which represents a point force, they require a substantial "head" of water in the downspout to uncoil the springs. As a result, the application of these devices is somewhat limited. For example, a 1.2 meter length of hose may be insufficient to remove water from adjacent a foundation or to cross a driveway or sidewalk. Moreover, in the known hoses using metal springs, the coiling mechanism is heat sealed within the hose. As a result, the hoses must be made of relatively expensive R.F. sealable material. In addition the capital costs, associated with manufacture of the hoses with metal springs, are high.
Finally, it is possible for metal springs to rust and corrode over time. This is especially problematic if the hose is intended to be used with water or corrosive liquids.
Prior art self coiling hoses of the type discussed above also suffer, in hot climates, from the vinyl or other plastic material being sealed along portions of their length, from the action of the sun. The heat from the sun may heat seal the inner surfaces of the tube together, thus destroying the tubular nature of the hose.
Thus, for many reasons, an improved automatically retracting hose is desired.